The New England Journal of Medicine even posted a study in 2006 that showed patients with cystic fibrosis who followed a course of treatment using salt for 48 weeks showed significant results without any adverse affects.

DITYATKOVSKAYA Ye,M., PISCOVAYA M., GRIBANOVA L. (1993).
State of immunoreactiveness of bronchial asthma for the period of treatment at chambers with salt mines artificial climate. In XIV World congress of asthmology - Interasma 93. Jerusalem, p. 84.